Here, memory component is intended to mean one or more memory chips packaged in a single package (e.g. TSOP package), and a memory module is intended to mean one or more memory components mounted on a printed circuit board.
Although applicable to any integrated circuits in principle, the present invention and the problems on which it is based are explained with reference to integrated memory chips in silicon technology.
FIG. 4 shows a schematic representation of a known memory module having a multiplicity of memory components, each containing a memory chip in silicon technology.
In FIG. 4, SC refers to a circuit board, on which, in order to form a memory module SM, a multiplicity of packaged memory chips, or rather memory components SB, are mounted and wired up to contacts SK to form a memory module SM.
According to usual standards, such memory modules SM, which are used for typical computers for example, must be able to output information on the specification so that they can be addressed correctly by the chipset of the computer concerned. This specification includes, for example, the type, the size, the manufacturer, details of clock speeds, serial number etc. The specification information must be stored in the memory module SM in a suitable way in non-volatile form, i.e. so it cannot be modified by the user.
For this purpose, the memory module SM consists of the actual memory chips SB, in SDRAMs (synchronous dynamic random access memory), and of what is known as a serial presence detect component SPD, namely an EPROM memory (electrically programmable read-only memory), in which the specification information of the memory module SM is stored in non-volatile form.
The EPROM memory SPD is connected to a special connection contact SP via a special data line SL. The specification information stored in the EPROM memory SPD can be read serially via this data line SL and the connection contact SP.
Furthermore, it is generally known to replace faulty storage capacitors in such memory chips SB with redundant storage capacitors using fuses or anti-fuses, as they are known.